The known aeration-type rotary dryer, such as a Roto-Louvre dryer, is highly efficient if materials are not sticky. However, it is expensive as compared with the ordinary or non-aeration rotary dryer, because of having a complicated double-wall cylinder and sealing means for sliding portions between the hot-air inlet and the air chambers. Besides, it is not suitable for sticky materials because of being incapable of preventing formation of lumps.
On the other hand, the non-aeration rotary dryer is simple in construction and available for drying sticky materials, but incapable of quick and efficient treatment.
The present invention is intended to resolve the problem as described above and provide an aeration-type rotary dryer that is relatively simple in construction and capable of quick and efficient treatment irrespective of the properties of materials.